A person's skin color is determined by many factors, such as the activity of melanocytes to make melanin pigment, distribution of blood vessel, thicknesses of skin, whether pigments such as carotenoid and hemoglobin, and the like are present inside and outside of the human body. Physiological factors related to genetic factors, secretion of hormone, stress, and the like and environmental factors such as UV irradiation have an effort on formation of the melanin pigment (Annu. Rev. Genet. 37:67-90, 2003).
A thing having a significant effect on a generation mechanism of the melanin is an enzyme called tyrosinase and the tyrosinase is involved in the oxidation of tyrosine in a melanosome in the melanocyte. The tyrosinase is activated by UV exposure to be applied to tyrosine to synthesize a melanin polymer by an oxidation process of generating 3,4-dihydroxyphenylalanine (DOPA) and DOPAquinone (J. Environ. Sci. Health. 23 (2): 105-161, 2005).
The melanin is present in an epidermal layer of the outside of the skin and serves to protect skin organs below the dermis from UV and the like and capture free radicals generated in the skin of the body to protect proteins and genes in the skin. However, it is known that when the melanin is over-produced, the melanin forms melasma, freckles, and the like and promotes skin aging, and plays an important role in causing skin cancer (FASEB J. 21(4): 976-994, 2007).
In order to treat or reduce skin dyspigmentation symptoms such as melasma, freckles, and pigmentation and excessive melanin pigmentation generated by UV exposure and the like, ascorbic acid, kojic acid, arbutin, hydroquinone, glutathione, or derivatives thereof, and materials having a tyrosinase-inhibiting activity are combined in cosmetics or medicines and have been used from before. However, the use of these materials is limited due to an insufficient whitening effect, a safety problem for the skin, formulation during combination of the cosmetic, and a stability problem (Dermatol. Ther. 20(5):308-313, 2007). Accordingly, in order to solve the problem of the active ingredients, the demand for the active ingredient derived from a natural material with proven safety and stability is proposed.
The stratum corneum of the skin is present in an outermost layer in the skin and directly in contact with an external environment to serve as an important barrier function to protect the body from external physical and chemical stresses. The barrier function is maintained by homeostasis of the epidermis. The epidermis homeostasis maintains the persistent skin barrier function by forming a skin barrier called a stratum corneum via terminal differentiation through a differentiation process according to growing division and cell migration of keratinocytes of a base layer (Korean J. Food. Sci. Technol. 43:458-463, 2011).
As the keratinocytes are differentiated, two factors affecting moisturizing are generated. First, while the keratinocytes are differentiated, the cell membrane thereof is replaced with a structure called a cornified envelope. The cornified envelope is a membrane structure in which many structural proteins including loricrin, involucrin, and filaggrin are cross-linked by an enzyme which is referred to as transglutaminases to provide a skin protection function for an external environment and suppress water evaporation in the corneous cells (Nat. Rev. Mol. Cell Biol. 6(4):328-340, 2005). The cornified envelope structural protein and the transglutaminases start to be expressed according to the differentiation of the keratinocytes to be used as differentiation markers (Nat. Rev. Mol. Cell Biol. 6(4):328-340, 2005). Therefore, the cornified envelope and the differentiation markers are used as a moisturizing index.
Further, during the differentiation process of the corneous cells, the keratinocytes generate natural moisturizing factors (NMF) to have a function as a skin barrier. A protein which is an important source for generating the NMFs is filaggrin and the filaggrin is decomposed to hydrophilic amino acids by caspase 14 to form the NMFs. The NMFs provide water holding capacity and moisture absorption in the air to functions to maintain the moisturizing ability in the skin (J. Cell Sci. 122:1285-1294, 2009). Accordingly, the maintaining of the NMFs in the skin at an appropriate level is a very important factor in skin health through the skin barrier function.
Fucosterol is a material which is largely included in algae and frequently discovered in algae inhabited on the coast in Asia including Korea, China, Japan, and the like. Until now, it is reported that the activity of the fucosterol includes anti-cancer (Pharmacogn. Mag. 8 (29): 60-64, 2012), anti-diabetic (Arch. Pharm. Res. 27 (11): 1120-1122, 2004), antioxidation (Bioorg. Med. Chem. 17 (5): 1963-1973, 2009), improved blood lipid ingredients (Biochem. Biophys. Res. Commun. 369 (2): 363-368, 2008), improved cholesterol metabolisms (New Phytol. 183 (2): 291-300, 2009), antimicrobial (J. Pharm. Biomed. Anal. 51 (2): 450-4555, 2010), antifungal (Nat. Prod. Res. 24(15): 1481-1487, 2010), anti-aging (Photochem. Photobiol. 89(4): 911-918, 2013), and the like. However, the skin whitening activity and the moisturizing activity of the fucosterol are not reported until now.
Throughout the specification, theses and patent documents are referenced and the citation thereof is represented. The disclosed contents of the cited theses and patent documents are entirely inserted with reference to the specification and thus, a level in the art and the contents of the present invention will be more clearly described.